It all depends on which model of the 4590 you have. If you have the 4590 copier/printer model then yes, the PS option is integrated on the board in the machine. All you need to do is download the driver, which is available here on Xerox.com, on the Support and Drivers pages. If you have the copier only model, you can purchase a Post Script kit to install on your machine. If you don't know whether your model is a copier only or a copier/printer model, then simply go to the control panel at the machine and press the Machine Information button. On the Machine Information screen you should see the serial number of your machine listed. If the first three characters are L74 you have the copier only model. If the first three characters are L75 you have the copier/printer model. If you have more questions please post back.